The present invention relates to an electron beam writing technique for use in a manufacturing process of a semiconductor integrated circuit. More specifically, the present invention relates to high-precision electron beam writing equipment and writing method.
In prior art electron beam writing equipment, the size of the fastest deflection field on a sample is about 50 μm square (for example, Sakitani et al.: Journal of Vacuum and Technology, B12, 1992, pp. 2759–2763).
To deflect the 50 μm square precisely, deflection is corrected. Specifically, an electron beam is deflected to near the corner of the deflection field to detect a mark for beam correction near it, thereby measuring and correcting a difference between a desired deflection distance and an actually measured deflection distance.
Electron beam writing equipment having a micro deflection field of about 2 μm square is proposed (for example, see Iwadate et al.: Journal of Vacuum and Technology, B5, 1987, pp. 75–78).
As a reliable method for making electron beam writing equipment faster, there is a multi beam method. In this method, plural electron beams arrayed at a predetermined pitch in a two-dimensional manner are used. The distance between the electron beams is short so that the fastest deflection field is about 2 μm square.
In the above prior art deflection correction method of 50 μm square, scanning above 2 μm is performed for mark detection itself. The prior art method cannot be applied to a 2 μm-square field. In the above prior art, a deflection correction method of such micro deflection field is not described.